Continuous-current transformer.



No. 645,774. Patented Mar. 20, I900. A. WYDTS 8:, G. WEISSMANN.

CONTINUOUS CURRENT TRANSFORMER.

(Appiication fired May 12, 1899.)

UNITED STATES PATENT OFFICE.

ALFRED WYDTS AND GUSTAVE WEISSMANN, OF PARlS, FRANCE.

CONTINUOUS-CURRENT TIQANSFORMER.

SPECIFICATION forming part of Letters Patent N 0. 645,774, dated March20, 1900.

Application filed May 12, 1899. Serial No. 716,568. (No model.)

To (0 20700772 it 77'tG/Z/ concern:

Be it known that we, ALFRED WVYDTS, electrical engineer, of 339 Rue desPyrnes, and GUSTAVE WEIssMANN, engineer, of 3 Rue Chaptal, Paris, in theRepublic of France, have invented an Improved Method of and Apparatusfor Transforming Continuous Electric Currents into Continuous Currentsof Different Voltage, of which the following is a full, clear, and exactdescription.

This invention relates to a novel method of transforming continuouselectric currents into currents of different voltage for the purpose ofenabling the utilization of a continuous current supplied at the fixedtension by any source of electricity.

Our invention consists in principle in rendering a continuous currentalternating in order to enable it to be readily transformed by means ofelectromagnetic induction, the secondary alternating current of thistransformer being then rectified by means of a commutator operated bythe same mechanical device as that employed for rendering the originalcontinuous current alternating in such a manner that the secondaryalternatingcurrentis rectified isochronously, because the phases of thesecondary current, although lagging behind or displaced relatively tothose of the primary current, are isochronous with them-that is, theintervals separating the phases of the secondary current are equal tothose separating the phases of the primary current. Our method ofcurrent transformation therefore comprises in principle the followingoperations: first, passing the continuous current, the voltage of whichis to be either increased or diminished, into the armature of acontinuous-current motor in such a manner that this continuous currentis transformed into an alternating current; second, causing thisalternating current to pass into the primary circuit of anelectromagnetic transformer of any suitable kind in order to obtain inthe secondary circuit an alternating current of the desired voltage;third, rectifying this alternating current, which has been brought tothe desired voltage in the manner described, by means of a rectifying orredressing commutator operatively connected with the device which hastransformed the original continuous current into an alternating oneforinstance, the rectifying-commutator may be keyed upon the same axis asthe collectors which have produced the deformation of the originalcontinuous current in such a manner that isochronism is assured betweenthe emissions of the inducing-current and those of the rectifiedsecondary alternating current.

Inorder that our invention may be readily understood, we haverepresented by way of example in the accompanying drawing a method ofpractically carrying the same into effect.-

Between the poles of a magnet or of an electromagnet NS there isdisplaced in the direction indicated by the arrowfa dynamo ai mature Aof the Gramme type, for example, provided with a collector C and twobrushes B and B. Upon the same axis as the collector C and rotating withit are fixed four continuous collecting-rings 1 2 3 4, communicating,respectively, with four brushes 1 2 3 4, which rest upon them, and twohalf-rings 5 and 6, each of which comes in contact alternately firstwith the brush 00 and then with the brush y, according to the positionof these two half-rings, which rotate, and are consequently displacedwith respect to the two brushes ac and y, which are fixed. These twobrushes are suitably insulated and supported at the extremities of across-piece D, resembling the brush-holder of an ordinary bipolardynamo. This part D, which for the purpose of adjustment is capable ofbeing turned about the axis a, enables the brushes 0c and y to bebrought into a suitable commutation plane.

The continuous collecting-rings 1 and 2 are respectively incommunication with two strips V Z of the collector C, whicharediametrically opposite one to the other. The rings 3 and 4communicate, respectively, with the two half-rings 5 and 6, whichconstitute the rectifying-commutator. The brushes B and B are incommunication, respectively, with the primary terminals E and E, throughwhich the continuous current to be transformed enters. The brushes 3 and4 are in communication with the secondary terminals F and F, at whichthe rcsultin g transformed continuous current is collected. The brushes1 and 2 are connected with the terminals H II, at which terminate theextremities of the primary wire of the monophase transformer T. ,The twoextremities of the secondary wire of this transformer terminate at thetwo terminals M M, which are connected to the brushes as and 11 of therectifying-commutator.

This novel form of apparatus operates in the following manner: Then acontinuous current is conducted to the terminals E E, the ring Acommences to rotate and its velocity increases until the counterelectrometive force developed in its coils tends to balance theelectromotive force which produces the movement.

The primary circuit of the transformer T by means of the brushes 1 and 2and of the rings 1 and 2 is the seat of an alternating electromotiveforce,,the tension or voltage of this electromotive force being equal tothat of the continuous current which passes through the brushes 1 B whenthese latter are in contact with the strips V Z of the collector C. Thistension is also equal in absolute value to the tension of this current,but with the sign when the collector has become displaced through onehundred and eighty degrees in the direction of rotation, (indicated bythe arrow f,) and it becomes zero when, as shown in the drawing, thediameter which joins the strips V Z is at right angles to the diameterwhich joins the brushes l3 and B at their point of contact with thecollector. An alternating electromotive force is thus produced in theprimarycircuitofthe transformerT. The secondary circuit is then the seatof an alternating electromotive force, the tension of which, as is wellknown, is a function of the ratio of the number of primary windings tothe number of secondary windings. It is also wellknown that the phase ofthis secondary electromotive force is displaced by a certain angle withrespect to that of the primary electromotive force. It is for thisreason that the brushes so y, which are in communication with theextremities of the secondary circuit, may be displaced themselves, asabove stated, by means of a cross-piece D, which supports them. It istherefore only necessary to ascertain the angle of adjustment, whichgives the maximum of electromotive force at the terminals F F. Thealternating current supplied by the secondary circuit of the transformerT is conducted by the brushes w y to the two halfrings 5 and o of therectifying-commutator in electrical communication with the twocontinuous rings 3 4, against which the brushes 3 4, connected with theterminals F F, bear. YVhen the direction of the current changes in thebrushes m g], the said brushes shift from the half-ring or sector 5 tothe sector 6, and vice Versa, and the current which reaches theterminals F F is therefore practically continuous.

Our invention enables a continuous current to be transformed withouttransforming the electrical energy into dynamic energy and the dynamicenergy into electrical energy, the process which has hitherto beenemployed and of which the efficiency is known to be very low.

Our novel form of transformer, which may be employed for any voltage, isespecially adapted for enabling the employment of the current suppliedby public distributing-stations at a tension of from one hundred and tento one hundred and twenty volts for all applications which requireeither a greater or a smaller voltage, it being very rarely the casethat, apart from illuminating purposes, the voltage of stations for thedistribution of electricity is applicable indifferent/1y to the Varioususes of which the electric current is capable. For example, it isfrequently required to charge a secondary battery which may occasionallycomprise no more than three or four elements. Assuming thatitis desiredto charge a battery of four elements each having fifty kilograms ofplates, it would be necessary, if the elements are connected fortension, to employ a current of five hundred and twenty watts at 10.4volts in the proportion of 2.6 volts per element; but seeing that acurrent of one hundred and ten volts only is available it would benecessary to interpose in the path of the charging-current a rhec-statcapable of absorbing the difference- 99.6 1;

that is to say, a rheostat of 2 ohms.

The energy thus transform ed into heat and entirely wasted amounts to 50a X 99. 6 o 4,980 watts per second. As the charging of the elementswould be completed in ten hours at this rate, it would be necessary toabsolutely waste 49.8 kilowatt hours in order to charge this battery offour kilowatt hours only. It is practically the same thing in the caseof the charging of electric-motor vehicles as at present performed bymeans of the ordinary current supplied to private persons by publicdistributin -stations. Electrotypers also are unable to utilize theordinary town current for their work, as, seeing that they require amaximum force of five to six volts, a very large part of the energywould be wasted in the manner above described. If it is a question ofdistributing motive force to small industries where motors of two tothree kilogram meters are sufficient, a low-tension current is still tobe preferred, because it is an extremely costly and a very delicateoperation to construct small motors capable of operating normally with acurrent of one hundred and ten volts, or thereabout. Ten or twenty voltmotors, on the other hand, are large wire motors. They are also strongand may be readily and inexpensively constructed. The same thing holdsgood with regard to lighting purposes. Low-tension lamps have a shortand thick filament and one which is consequently not fragile. They arecapable of supporting a current far greater than that to which lampsprovided with fine filaments can be exposed with impunity. The result isa higher illuminating power.

Electrolysis in general, electrometallurgy, the use of electricfurnaces, &c., require intense currents of relativelyrlow tension,whichhitherto always necessitated special installations, as the ordinary towncurrent does not give satisfactory results. With our device, on theother hand, electrotyping, the charging of secondary batteries, &c., maybe car ried out under very good conditions, as the secondary current isabsolutely ml at the moment when the brushes a; y pass onto differenthalf-rings upon the rectifying-commutator. Consequently there is no fearof sparking taking place upon this commutator, and the brushes 0c 3/ maytherefore completely leave one half-ring before coming in contact withthe other half-ring. As a result of this the two terminals F F, which bymeans of the collecting-rings 3 4 are in communication with therectifying-commutator, are never short-circuited, a result which has nothitherto been obtained with ordinary rectifiedcurrent machines. In thecase of other applications of which the electric current is capable itmay, on the contrary, be necessary to increase the tension. Acontinuous-current transformer is indispensable in this case also. Manyforms of continuous current rotary transformers are in existence; buttheir low efficiency is well known. (They are of the coupled motor anddynamo type). In the case of low powers especiallytheir efliciency doesnot always attain twenty-five per cent. For this reason the employmentof a rheostat, although also extremely wasteful, is often preferred onaccount of its great simplicity.

Our form of transformer enables still further combinations to beobtained. Thus if instead of taking the current at the terminals F F itis taken at M M an alternating current may be obtained which is ofeither low or high tension, according to the method of winding thetransformer, or an alternating current of the same maximum tension orvoltage as the original continuous current may be obtained at H H. Themean or efficient electromotive force of said alternating current isabout seven-tenths of the electromotive force of the original continuouscurrent, for if the continuous electromotive force at E E is called 8,the efficient alternating electromotive force 8 at H H is In our form oftransformer the two eX- tremitics of the secondary circuit of the elec-8 110=77.7 volts.

troma-gnetic transformer T may be connected with the terminals F F,which correspond to the brushes 3 4t, and the rectified current is thenobtained upon the brushes 2: y. WVe also reserve the right to employ inour novel apparatus a multipolar electric motor for the purpose eitherof increasing the frequency of the current or of actuating polyphasetransformers.

It will of course be understood that we are at liberty to establish ournovel transformer in any suitable form to vary the dimensions and theconst ructional details according to the various applications of whichit is capable without in any way altering the principle of ourinvention.

We claim- 1. An electrical apparatus comprising a direct-currentgenerator, stationary currentconveying devices, such as brushes,connected with said generator, field-magnets, a rotary armatureconsisting of coils and collector-sections the number of which isgreater than that of said current-supply brushes, which are adapted toengage said sections, stationary collecting devices for taking an al-.ternating current off the same collector-sections as they rotate withthe armature, a transformer for converting the said alternating currentinto one of difierent voltage, and a rectifier operatively connectedwith the armature to move synchronously therewith, said rectifierconsisting of a rotary ring divided into as many sections as there arepole-pieces of the field-magnets, stationary brushes con nected with thesecondary coil of the transformer and engaging said ring, a plurality ofcontinuous rotary rings, one for each section of the divided ring andconnected with said sections individually, and stationarycollecting-brushes engaging said continuous rings.

2. An electrical apparatus comprising a direct-current generator,stationary currentconveying devices, such as brushes, connected withsaid generator, field-magnets, a rotary armature consisting of coils andcollector-sections the number of which is greater than that of saidcurrent-supply brushes, which are adapted to engage said sections,stationary collecting devices for taking an alternating current off thesame collector-sections as they rotate with the armature, a transformerfor converting the said alternating current into one of differentvoltage, and a rectifier operatively connected with the armature to movesynchronously therewith, said rectifier consisting of a rotary ringdivided into as many sections as there are polepieces of thefield-magnets, stationary brushes connected With the secondary coil ofthe transformer and engaging said ring, a plurality of continuous rotaryrings, one for each section of the divided ring and connected with saidsections individually, and stationary collecting-brushes engaging saidcontinuous rings, said transformer=brushes being secured to anadjustable support mounted to swing about the axis of rotation of therectifier-rings.

3. An electrical apparatus comprising fieldmagnets, a rotary armature,stationary devices, such as brushes, for conveying a current to saidarmature, collecting devices for taking an alternating current off thesame points of the armature as said points rotate with the armature, atransformer for converting the said alternating current into one ofdifferent voltage, and a rectifier consisting of a ring rotating withthe armature and divided into as many sections as there are pole-piecesof the field-magnets, a number of continuous rings rotating with thearmature and each connected with one of the sections of the dividedring, and stationary collecting devices, such as brushes, engaging thecontinuous rings and the section-ring respectively, one set of saidcollecting devices being connected with the transformer, and the otherwith the consumption apparatus, and a support carrying thosecollecting-brushes which engage the sectional ring, said support beingmounted to turn, for adjustment, about the axis of the armature.

4. An electrical apparatus comprising fieldmagnets, a rotary armature,stationary devices, such as brushes, for conveying a current to saidarmature, a direct-current generator connected with said brushes,collecting devices for taking an alternating current off the same pointsof the armature as said points rotate with the armature, a transformerfor converting the said alternating current into one of differentvoltage, and a rectifier operatively connected with the armature to movesynchronously therewith, to convert the lastmentioned alternatingcurrent into a continuous one.

5. An electrical apparatus comprising fieldmagnets, a rotary armature,stationary devices, such as brushes, for conveying a current to saidarmature, a direct-current generator connected with said brushes,collecting devices for taking an alternating current off the same pointsof the armature as said points rotate with the armature, a transformerfor converting the said alternating current into one of differentvoltage, and a rectifier consisting of a ring rotating with the armatureand divided into as many sections as there are pole-pieces of thefield-magnets, a number of continuous rings rotating with the armatureand each connected with one of the sections of the divided ring, andstationary collecting devices, such as brushes, engaging the continuousrings and the sectional ring respectively, one set of said collectingdevices being connected with the transformer,and the other with theconsumption apparatus.

6. An electricalapparatus comprising field magnets, a rotary armature,stationary devices, such as brushes, for conveying a current to saidarmature, collecting devices for taking an alternating current off thesame points of the armature as said points rotate with the armature, atransformer for converting the said alternating current into one ofdifferent voltage, and a rectifier consisting of a ring rotating withthe armature and divided into as many sections as there are pole-piecesof the field-magnets, a number of continuous rings rotating with thearmature and each connected with one of the sections of the dividedring, and stationary collecting devices, such as brushes, engaging. thecontinuous rings and the sectional ring respectively, one set of saidcollecting devices being connected with the transformer, and the otherwith the consumption apparatus, those collecting devices whichengage-the sectionaLring being adjustable by turning them about the axisof the armature.

The foregoing specification of our improved method of and apparatus fortransforming continuous electric currents into continuous currents ofdifferent voltage signed by us this 10th day of April, 1899.

ALFRED WYDTS. GUSTAVE WEISSMANN. Witnesses:

EDWARD P. MAOLEAN, MAURICE HENRI PIGNET.

